Postoperative nausea and vomiting (PONV) are common complications following anesthesia and surgery, with a nausea incidence of 22% to 38% and vomiting 12% to 26%. Factors contributing to PONV include patient characteristics (like young age and female gender), type of anesthesia, and specific surgical procedures. Various prophylactic treatments such as 5-HT3 receptor antagonists and corticosteroids can be effective in reducing the risk of PONV, with ondansetron and dexamethasone being among the most commonly recommended medications.

1. MODERATOR : DR BALWINDER
KAUR REKHI
PRESENTOR: DR LOVEPREET
POST OPERATIVE NAUSEA
AND VOMITING

2. INCIDENCE
 PONV- two of the most common and unpleasant side
effects following anaesthesia and surgery.
 Incidence of nausea- 22% to 38%
 Incidence of vomiting-12% to 26%
 An episode of vomiting prolongs postanaesthetic
care unit stay by about 25 minutes.

3. SIGNIFICANCE OF PONV
PONV remains a significant problem in modern anesthetic
practice because of adverse consequences such as
delayed recovery
unexpected hospital admission
delayed return to work of ambulatory patients
pulmonary aspiration
wound dehiscence
Considering increasing demand for ambulatory and day
care surgery, a holistic approach should be attempted
before and during surgery to prevent PONV.

4. DEFINATION
 NAUSEA
It is an unpleasant sensation referred to a desire to vomit not
associated with expulsive muscular movement.
 VOMITING
It is the forceful expulsion of even a small amount of upper
gastrointestinal contents through mouth.

5. CLASSIFICATION
 Early PONV- within 6 hrs of emergence from
anesthesia
 Late PONV- 6-24 hrs after procedure

6. PATHOPHYSIOLOGY
The neuro anatomical site controlling nausea and vomiting is an
ill-defined region called ‘vomiting centre’ within reticular
formation in the brainstem.
It recieves 5 primary afferent pathways :
1. The chemoreceptor trigger zone (CTZ) : It lies outside
BBB and is in close contact with CSF to interact . Adsorbed
toxins ,drugs ,circulating in blood stimulate CTZ .
2. Reflex afferent pathway from cerebral cortex
3. Neuronal pathways from vestibular system
4. The vagal mucosal pathway in the gastrointestinal
system.
5. Midbrain afferents

7. These afferents stimulate the vomiting centre and initiate the process of
vomiting by sending efferent signals . There occur coordinated contraction
of abdominal muscles against closed glottis. The pyloric sphincter contracts
and esophageal sphincter relaxes and there is active antiperistalsis within
esophagus which forcibly expels the gastric contents.
Stimulation of any of these afferent pathway can activate the sensation of
vomiting via various receptors
 Serotonergic( 5HT3)
 Dopaminergic(D2)
 Histaminergic (H1)
 Cholinergic (muscarinic)(M)
 NK1 receptor

9. ETIOLOGY
 The etiology of PONV is usually multifactorial and
associated with anesthetic and analgesic agents, the
type of surgical procedure, intrinsic patient factors
such as history of motion sickness
 It is important to recognize that nausea is common
complain reported at the onset of hypotension,
particularly following spinal or epidural anesthesia.

11. RISK FACTORS FOR PONV
 Patient factors
- young age
- female gender ( particular menstruating on day of
surgery or first trimester of pregnancy)
- nonsmoker ( 1.8 times more)
- history of prior postoperative emesis
- history of motion sickness
 Anesthetic technique
- general anaesthesia > epidural > SAB > PNB
- drugs: opioids, volatile agents, nitrous oxide

12.  Surgical procedure
- strabismus surgery
- ear surgery
- laparoscopy
- orchiopexy
- ovum retrieval
- tonsillectomy
- breast surgery
 Postoperative factors
- posteroperative pain
- hypotension

13. RULE OUT
 Hypotension
 Hypovolemia
 Postoperative pain
 Inadequate oxygenation
 Temperature- hypothermia, or patient feels too
warm
 Poor oral hygiene
 Foul or upsetting smell in the vicinity of the patient

14. APFEL SCORE
RISK FACTORS POINTS
FEMALE 1
NON SMOKERS 1
HISTORY OF PONV AND/ OR MOTION SICKNESS 1
POST- OPERATIVE OPIOID ADMINISTRATION 1
POINTS SCORE % RISK OF PONV
0 10
1 20
2 40
3 60
4 80
LOW RISK
HIGH RISK

15. PONV : DRUGS FOR PROPHYLAXIS AND T/T
 5HT3 RECEPTOR ANTAGONIST:
- Ondansetron
-Granisetron
-Dolasetron
-Palonsetron
 CORTICOSTEROIDS
-Dexamethasone
 DOPAMINE ANTAGONIST
-Metoclopramide
-Prochlorperazine
 BUTYROPHENONES
-Droperidol
-Haloperidol

16.  ANTIHISTAMINES
-Promethazine
-cyclizine
-dimenhydrinate
 ANTICHOLINERGIC
-Transdermal Scopolamine
 NK-1 RECEPTOR ANTAGONIST
-Aprepitant
 PROPOFOL
 GABAPENTINE
 MIDAZOLAM

17. 5HT3 ANTAGONIST
 Selectively block 5-HT3 receptors of GI tract and CTZ in area postrema of
brain.
ONDENSETRON:
FDA dose- 4mg iv
plasma ½ life -3 hours (most effective when given at the end of surgery)
Reduce risk by 26%
S/E: Headache , nausea, slight prolongation of QT interval , allergic reactions
Metabolism-ondensetron undergoes extensive metabolism in liver via
hydrolation and cojugation by cytochrome P-450 enzymes.
Dose should be reduced in liver failure.

18.  DOLASETRON
FDA Dose : 12-50 mg
iv- 12.5mg
oral- 25-30 mg
Plasma ½ life- 7 hours ( at induction)
Not recommended due to QT prolongation.
 GRANISTRON
FDA Dose: 1mg( 20-40 ug/kg)
Plasma ½ life -9 hours ( at induction)

19.  PALANOSETRON
Most effective antiemetic in this group with NK-1
antagonism.
FDA Dose-0.075 mg iv
Reduce the risk by 30% with ½ life of 40 hrs ( usually
given at the start of surgery)
Most useful in PDNV

20.  DEXAMETHASONE
MOA- Inhibition of corticosteroid receptors inNTS
Inhibition of prostaglandins synthesis
FDA Dose – 4-5mg iv
Slower in onset
Administer at the induction
Complication-Perioperative hyperglycemia in DM and
obese patients, post op infection.

21. BUTYROPHENONES
 DROPERIDOL
MOA: It is relatively selective D2 receotor antagonist .
It is very effective in small doses ( 0.625-1.25mg iv)for prevention and treatment
of PONV.
Plasma ½ life of 3 hours
Risk reduced by 26%
FDA has given Black box warning
Unfortunately its use has declined after its association with rare fatal arrythmias
Contraindicated in suspected QT prolongation.
S/E: Anxiety , restlessness ,akathsia,dystonia, torsedes de pointes.

22. METOCLOPRAMIDE
FDA Dose – 10mg iv ( 0.2-0.5 mg/kg)
MOA- D2 receptor antagonist both central( CTZ) and
peripheral.
Peripheral prokinetic activity
COMPLICATIONS- EPS, hypotension, tachycardia
CONTRAINDICATED- Parkinson’s disease, restless
leg syndrome.

23. NK1 ANTAGONIST
APREPITANT
MOA: Blocks NK1 receptors present in GIT
FDA Dose – 40mg orally ( at induction)
Risk reduced by 69%
High cost

24. ANTIHISTAMINES
PROMETHAZINE
DIPHENHYDRAMINE
CYCLIZINE
MOA: H1 antagonism and anti cholinergic activity.
S/E: Drowsiness , urinary retention ,
dry mouth,blurred vision.
Given at the start –sedative side effects may delay
recovery if given at end of surgery.

25.  PROPOFOL
The median plasma propofol concentration associated
with an antiemetic response was 343ng/ml , which is
much lower than the concentration ranges associated
with general anaesthesia( 3-6 mcg/ml) or sedation (1-
3mcg/ml)
Propofol in small doses (20mg as needed) can be used
as rescue therapy.

26. GABAPENTINE
600mg orally given 2 hours before surgery
800mg 1hour before surgery.
MIDAZOLAM
Midazolam 2mg when administered 30 mints before
the end of surgery was as effective against PONV as
ondensetron 4mg.

33. 5 HT antagonists and dexamethasone are the
most effective antiemetics in the prophylaxis of
pediatric POV.